Small peeks in ModelSim simulation

Dear all,

following problem: I have running a full-adder with a testbench, comming up with a peek in the output signal!

So, it is not a signal from 0 to 1 or 1 to 0 for a certain duration, it is really just a line!

It occurs everytime when 2 of my three input signals change at the same time, meaning:

a: 0 --> 0

b: 0 --> 1

c: 1 --> 0

How can I avoid this? Would this effect outputs on the HW?

Thanks, MW